I had a scare last weekend that anyone with a navaid autopilot with a wingtip-mounted servo should be aware of.
During preflight, I lifted the right aileron and upon reaching full displacement, found it locked in place - fully displaced. I removed the right wingtip and found that the drift pin in securing the servo arm to the servo shaft had fallen out. The arm had fallen off the shaft and the pushrod dropped onto the lower edge of a hole in the end rib. The pushrod was segmented with telescoped sections of tubing. When I lifted the aileron, the pushrod pulled back through the opening dropped, over the step of the telescoped pushrod and was effectively locked against return to neutral. I had noticed that the Navaid was nonfunctional for the prior 10 hours or so. Gives me the creeps to think what would have happened if the same would have happened in flight.
It appeared that the pin was a simple friction fit from the factory.
Two fixes were employed. The pin is now a TIGHT friction fit with loctite and the step in the pushrod gone.
If it happened once, it could happen again - to you.
During preflight, I lifted the right aileron and upon reaching full displacement, found it locked in place - fully displaced. I removed the right wingtip and found that the drift pin in securing the servo arm to the servo shaft had fallen out. The arm had fallen off the shaft and the pushrod dropped onto the lower edge of a hole in the end rib. The pushrod was segmented with telescoped sections of tubing. When I lifted the aileron, the pushrod pulled back through the opening dropped, over the step of the telescoped pushrod and was effectively locked against return to neutral. I had noticed that the Navaid was nonfunctional for the prior 10 hours or so. Gives me the creeps to think what would have happened if the same would have happened in flight.
It appeared that the pin was a simple friction fit from the factory.
Two fixes were employed. The pin is now a TIGHT friction fit with loctite and the step in the pushrod gone.
If it happened once, it could happen again - to you.